MARTA’s general manager and its chief legislative overseer locked horns today over the transit agency’s plan to spend up to $400,000 on outside lobbyists. Then, state Rep. Jill Chambers butted heads with a member of her MARTA Oversight Committee. Chambers grilled MARTA officials this morning about several million dollars in spending that she regarded as unnecessary. When Sen. Doug Stoner objected to her tone, Chambers cut off his microphone. “I’m very disappointed in us as a committee,” Stoner said. “We’re playing games.”